1. Field of the Invention
The present invention relates to a method of synthesizing 1,4-bis(chlorodifluoromethyl)benzene). More particularly, the present invention relates to a method of synthesizing 1,4-bis(chlorodifluoromethyl)benzene) in a high yield by using a batch process or a continuous process, which has simple processes and short reaction time.
2. Description of Related Art
By chemical vapor deposition (CND) processes in vacuum pyrolysis, parylene polymers can be formed into ultra-thin films, which have many excellent properties such as electrical property, heat resistance, chemical stability, high transparency, etc. Accordingly, parylene polymers have been commonly used in thin films and coatings and widely applied in many areas such as electrical isolation in printed circuit boards, moisture proofing in sensors or medical equipment, electrical insulation in electronic devices, protective coatings, packaging materials, anticorrosion for metal coating, etc.
Currently, fluorinated parylene such as poly(tetrafluoro-p-xylene) represented by the following formula (1) has been applied to dielectric films used in electronics and coating industries owing to its high boiling point, low-dielectric constant, and good anti-ultraviolet and anti-aging properties.

Presently, a method of coating with fluorinated parylenes is to polymerize active monomers on the surface of an object. Unlike the general steps of liquid coating process, this coating process is executed as follows: heating and vaporizing fluorinated para-xylene dimers such as octafluoro-(2,2)-paracyclophane (AF4) represented by the following formula (2), converting the dimers into free radicals of fluorinated para-xylene monomers by prolysis, and then polymerizing the monomers on the object to form poly(tetrafluoro-p-xylene), which is called parylene FIT represented by formula (1).

1,4-bis(chlorodifluoromethyl)benzene (CFB) represented by the following formula (3) is an important precursor for preparing fluorinated parylene dimmers (AF4).

A conventional method of preparing 1,4-bis(chlorodifluoromethyl)benzene comprises the following steps: dissolving 1,4-bis(difluoromethypbenzene in a solvent such as carbon tetrachloride (CCl4) to form a reactant solution; providing a photo initiator and introducing chlorine gas into the reactant solution; and initiating the reaction by light irradiation under the catalysis of the photoinitiator so as to obtain 1,4-bis(chlorodifluoromethyl)benzene. However, the method has several disadvantages in that: (1) long reaction time; (2) low yield; (3) addition of a photoinitiator or a solvent such as CCl4 is required, which is not eco-friendly; (4) complex processes for purification; and (5) consuming high amounts of energy to obtain products.
Therefore, it is desirable to provide a rapid, simple and low cost method of synthesizing 1,4-bis(chlorodifluoromethyebenzene for mass production. The present invention provides a simple, low cost method of synthesizing 1,4-bis(chlorodifluoromethyl)benzene used as an important precursor for preparing fluorinated para-xylene dimers,